The paper reports on an update of previous studies, and the results are reported mainly as changes from the previous material to reflect the impact that changes in the modelling decisions.
I can't tell where the 2.1 cm to 5 cm numbers come from (searching the paper for "2.1" is interesting).
It reports the expected 2100 see level rise from Greenland ice melt of 6 different scenarios, in two methodologies. The low, low stddev at 3.7 cm, and the high, high stddev at 25.6 cm.
And of course sea level may also be rising from other sources, that just isn't covered in the paper you mention.
You get to pick your personal items to worry about based on your individual assumptions and interests, but if your opinion is based in part on that specific paper you might want to reread it.
I'm not sure where you got those. IPCC 2019 report estimated the Greenland contributions in the 10-30cm range, and the link you gave is mostly about newer models suggesting a bit higher than 2019 IPCC, so suggest at the higher end (or above) of that range.
The only related thing I could find in your linked report was to estimate contributions up by 2.6cm/2.8 cm/5cm (different scenarios) from CMIP5 to CMIP6, not in total. Maybe I missed something?
That carbonbrief article links to the underlying paper at : https://www.nature.com/articles/s41467-020-20011-8
The paper reports on an update of previous studies, and the results are reported mainly as changes from the previous material to reflect the impact that changes in the modelling decisions.
I can't tell where the 2.1 cm to 5 cm numbers come from (searching the paper for "2.1" is interesting).
Here is a table from the paper reported as total sea level impact estimates and 1 stddev range, rather than deltas : https://www.nature.com/articles/s41467-020-20011-8/tables/1
It reports the expected 2100 see level rise from Greenland ice melt of 6 different scenarios, in two methodologies. The low, low stddev at 3.7 cm, and the high, high stddev at 25.6 cm.
And of course sea level may also be rising from other sources, that just isn't covered in the paper you mention.
You get to pick your personal items to worry about based on your individual assumptions and interests, but if your opinion is based in part on that specific paper you might want to reread it.